From b4c6a39ccf051c9a05956d25e8b075659ae60d1c Mon Sep 17 00:00:00 2001
From: Tim Neumann <mail@timnn.me>
Date: Thu, 4 Aug 2016 15:18:36 +0200
Subject: [PATCH] change depr_map to use DeprecationEntry

---
 src/librustc/middle/stability.rs | 57 +++++++++++++++++++++++++++-----
 1 file changed, 48 insertions(+), 9 deletions(-)

diff --git a/src/librustc/middle/stability.rs b/src/librustc/middle/stability.rs
index 36268a9de96..209b44e67a1 100644
--- a/src/librustc/middle/stability.rs
+++ b/src/librustc/middle/stability.rs
@@ -19,7 +19,7 @@ use session::Session;
 use lint;
 use middle::cstore::LOCAL_CRATE;
 use hir::def::Def;
-use hir::def_id::{CRATE_DEF_INDEX, DefId};
+use hir::def_id::{CRATE_DEF_INDEX, DefId, DefIndex};
 use ty::{self, TyCtxt};
 use middle::privacy::AccessLevels;
 use syntax::parse::token::InternedString;
@@ -61,12 +61,46 @@ enum AnnotationKind {
     Container,
 }
 
+/// An entry in the `depr_map`.
+#[derive(Clone)]
+pub struct DeprecationEntry {
+    /// The metadata of the attribute associated with this entry.
+    pub attr: Deprecation,
+    /// The def id where the attr was originally attached. `None` for non-local
+    /// `DefId`'s.
+    origin: Option<DefIndex>,
+}
+
+impl DeprecationEntry {
+    fn local(attr: Deprecation, id: DefId) -> DeprecationEntry {
+        assert!(id.is_local());
+        DeprecationEntry {
+            attr: attr,
+            origin: Some(id.index),
+        }
+    }
+
+    fn external(attr: Deprecation) -> DeprecationEntry {
+        DeprecationEntry {
+            attr: attr,
+            origin: None,
+        }
+    }
+
+    pub fn same_origin(&self, other: &DeprecationEntry) -> bool {
+        match (self.origin, other.origin) {
+            (Some(o1), Some(o2)) => o1 == o2,
+            _ => false
+        }
+    }
+}
+
 /// A stability index, giving the stability level for items and methods.
 pub struct Index<'tcx> {
     /// This is mostly a cache, except the stabilities of local items
     /// are filled by the annotator.
     stab_map: DefIdMap<Option<&'tcx Stability>>,
-    depr_map: DefIdMap<Option<Deprecation>>,
+    depr_map: DefIdMap<Option<DeprecationEntry>>,
 
     /// Maps for each crate whether it is part of the staged API.
     staged_api: FnvHashMap<ast::CrateNum, bool>
@@ -77,7 +111,7 @@ struct Annotator<'a, 'tcx: 'a> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     index: &'a mut Index<'tcx>,
     parent_stab: Option<&'tcx Stability>,
-    parent_depr: Option<Deprecation>,
+    parent_depr: Option<DeprecationEntry>,
     access_levels: &'a AccessLevels,
     in_trait_impl: bool,
 }
@@ -184,14 +218,15 @@ impl<'a, 'tcx: 'a> Annotator<'a, 'tcx> {
 
                 // `Deprecation` is just two pointers, no need to intern it
                 let def_id = self.tcx.map.local_def_id(id);
-                self.index.depr_map.insert(def_id, Some(depr.clone()));
+                let depr_entry = Some(DeprecationEntry::local(depr, def_id));
+                self.index.depr_map.insert(def_id, depr_entry.clone());
 
-                let orig_parent_depr = replace(&mut self.parent_depr, Some(depr));
+                let orig_parent_depr = replace(&mut self.parent_depr, depr_entry);
                 visit_children(self);
                 self.parent_depr = orig_parent_depr;
-            } else if let Some(depr) = self.parent_depr.clone() {
+            } else if let parent_depr @ Some(_) = self.parent_depr.clone() {
                 let def_id = self.tcx.map.local_def_id(id);
-                self.index.depr_map.insert(def_id, Some(depr));
+                self.index.depr_map.insert(def_id, parent_depr);
                 visit_children(self);
             } else {
                 visit_children(self);
@@ -685,6 +720,10 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
     }
 
     pub fn lookup_deprecation(self, id: DefId) -> Option<Deprecation> {
+        self.lookup_deprecation_entry(id).map(|depr| depr.attr)
+    }
+
+    pub fn lookup_deprecation_entry(self, id: DefId) -> Option<DeprecationEntry> {
         if let Some(depr) = self.stability.borrow().depr_map.get(&id) {
             return depr.clone();
         }
@@ -703,12 +742,12 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
         }
     }
 
-    fn lookup_deprecation_uncached(self, id: DefId) -> Option<Deprecation> {
+    fn lookup_deprecation_uncached(self, id: DefId) -> Option<DeprecationEntry> {
         debug!("lookup(id={:?})", id);
         if id.is_local() {
             None // The stability cache is filled partially lazily
         } else {
-            self.sess.cstore.deprecation(id)
+            self.sess.cstore.deprecation(id).map(DeprecationEntry::external)
         }
     }
 }